Algebra 1 Ratios and Proportion

This lesson will teach you all about Ratios and Proportions. Beginning with definitions and illustrative examples, you will move quickly into cross products and cross multiplication before seeing rates in mathematics and their counterparts in real life. Four video examples at the end make sure you know how to use your new found knowledge.

Ratios and Proportion

A ratio is a comparison of two quantities by division.

A proportion is an equation stating that two ratios are equal.

Two ratios are equal if and only if their cross products are equal. To solve a proportion, use the fact that the cross products are equal. Set the cross products equal to each other and solve for the unknown value.

A rate is a ratio of two quantities having different units of measurement.

Solve problems involving rates by using proportions.

A scale is a ratio that compares the size of a model to the size of the actual object. Proportions can be used to solve problems involving scales.

Ratios and Proportion

The temperature increases from thirty to sixty degrees. What is the percent of change?

A suit was originally $160, but is discounted 30% . A sales tax of 7.5% is added, based on the discounted price. What is the final price of the suit? To the nearest percent, what is the percent of change between the original price and the final price paid, including sales tax?

A camera was originally $225, but is discounted 15% . A sales tax of 7.5% is added, based on the discounted price. What is the final price of the camera? To the nearest percent, what is the percent of change between the original price and the final price paid, including sales tax?

*These practice questions are only helpful when you work on them offline on a piece of paper and then use the solution steps function to check your answer.

Answer

Ratios and Proportion

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.